Journal of
Science and Technology-The University of Danang, JST-UD, is an
independent peer-reviewed journal, applying international standards, inheriting
the achievements of 40 years of scientific and technological information
activities of Da Nang University and member institutions.
JST-UD operates under License No. 510/GP-BVHTT, dated November 25, 2002
by the Ministry of Culture and Information and international standard code ISSN
1859-1531 (according to Official Letter No. 44/TTKHCN-ISSN, February 6, 2007 of
the National Center for Scientific and Technological Information under the
Ministry of Science and Technology). It is a scientific journal with a high
number of access and reference.
JST-UD publishes quality scientific works in Vietnamese, English or
French (License No. 210/CBC, 5 March 2008 of the Press Department, Ministry of
Information and Communication) and Published yearly 15 numbers, including 3 in
English (License No. 07 / GP-BTTTT, January 7, 2016 by the Ministry of
Information and Communication).
The Journal
"Science and Technology" of the University of Danang is for purposes:
- Publishing new and multi-disciplinary
scientific and technological research works;
- Reviewing information on advances in
science and technology for the teaching, research and study of lecturers and
students;
- Propagating the guidelines and policies
of the Party and the State in the fields of education, training as well as in
scientific and technological researches.
JST-UD is pleased to receive many-sided cooperations of scientists,
educators, researchers in and outside the University of Danang as well as
national and international researchers to improve the prestige and the quality
of the Journal.
CURRENT ISSUE | Vol. 18, No. 1, 2020
Author: , Lê Hoài Nam
Code: JST-UD2019-133 | Page: 1-6 of Vol. 18, No. 1, 2020 |
AbstractNowadays, the agriculture wastes are causing extreme influence on the environment, quality of life, and people's health. One of the solutions to this problem is using vermicompost - a process of organic material degradation using earthworms (Peryonyx Excavatus), to create a heterogeneous mixture of decomposing vegetable or food waste, bedding materials, and vermicast. This article presents the evaluation of the earthworm ability in agricultural wastes treatment, then the design and manufacturing of an automatic vermicompost system using IoT.This proposed system helps to solve several problems such as reducing labor, area; increasing waste treatment efficiency as well as increasing efficiency of vermicast raising; easy operation and scalability, automatical and good control over the process of raising earthworms
Author: , Fabien Ferrero, Lê Công Vĩnh Khải, Nguyễn Huỳnh Nhật Thương, ,
Code: JST-UD2019-209 | Page: 7-10 of Vol. 18, No. 1, 2020 |
AbstractThe development of IoT applications is lightning-fast in terms of technology and solutions in all areas of life. This brings both opportunity and challenges for IoT application which require IoT devices to consume low energy and be able to exchange data with long distance. LoRa (Long Range) is the new wireless communication standard in recent years to address these challenges.Although the industrial LoRaWAN network shows its outstanding ability in long range data transmission, the LoRa signal is still practically attenuated by the transmission distance, buildings, trees and other radio signal sources. In this paper, we propose a low-power LoRa information network model for IoT applications with long-distance transmission and assess LoRa coverage in Da Nang City with two industrial IoT LoRaWAN Gateways and other gateways.
Author: , Nguyễn Ngọc Quế, Trương Thanh Hải, Tiêu Hà Hồng Nhân
Code: JST-UD2019-211 | Page: 11-16 of Vol. 18, No. 1, 2020 |
AbstractAgricultural tractors are one of the key means to successfully implement agricultural mechanization in Vietnam. Choosing the right type of tractor and the traction layer ensure the suitability when the tractor works in Vietnamese fields.
Based on the use of SIMCENTER software, we have conducted a calculation analysis of the traction-adherence feature of the Thaco tractor, done simulations to find the optimal specifications of the tractor to ensure that the tractor works well, has the traction-adherence ability to grip the Vietnamese field.
On the other hand, we have also analyzed the effects of the structural parameters, the conditions of use affecting the traction-adherence feature and the working ability of the tractor, built a simulation program for traction-adherence features and the working ability of Thaco tractors on specific land in Vietnam.
Author:
Code: JST-UD2019-073 | Page: 17-22 of Vol. 18, No. 1, 2020 |
AbstractThe unconfined compressivestrength test is to determine the compressive resistance strength of the soil sample, characterizing the bearing capacity of the soil ground. The author uses trixial compression device to perform the unconfined compressive strength test with the advantage that Loadcell records the automatic reading instead of the mechanical clock reading of the crank device. Experiments have recorded the results of 3 soil groups as follows: For sandy soil with gravels, plastic state gravel (viscosity B from 0,29 to 0,37; number of SPT from 7 to 12 hammers), the compressive resistance strength changes from 62,08 to 105,55 kN/m2. For sandy clay with gravels, soft plastic state (viscosity B from 0,49 to 0,61; the number of SPT from 2 to 7 hammers), the compressive resistance intensity varies from 48,95 to 99,77 kN/m2. With sandy clay with gravels, stiff state (viscosity B from 0,21 to 0,42; number of SPT from 7 to 19 hammers), the compressive resistance intensity varies from 52,78 to 162,69 kN/m2.
Author: ,
Code: JST-UD2019-174 | Page: 23-26 of Vol. 18, No. 1, 2020 |
AbstractAfter pre-treatment, the wastewater from seafood processing plant has a high concentration of organic matters and nutrients. With the unstable regime of influent depends on the changes of daily amount of raw seafood, it is fairly difficult to maintain the quality of treated water to discharge standards.
This paper presents the results of the possibility of increasing the organic loading and the parameters for aerobic process bio-carriers addition. The results show that: (1) With bio-carriers, the aeration tank has the ability to increase the organic loading compared to traditional one; (2) Among the bio-carriers considered, the efficiency increasing with carriers is BK-Biocarrier 4mm, BK-Biocarrier 2mm and PVAGel, respectively; (3) When operating the aeration tank with BOD5 treatment efficiency of 80%, the organic loading increases 1.84 times with 10% PVAGel carrier addition (corresponding with 0.95gBOD5/g(slude).day) and 1.5 times when adding 10% BK-Biocarrier 2mm (corresponding with 0.78gBOD5/g(sludge).day).
Author: Đức Tuấn Hồ*, , Mai Đức Nghĩa
Code: JST-UD2019-109 | Page: 27-30 of Vol. 18, No. 1, 2020 |
AbstractThe paper presents the results of experimental research on the effect of pressure of the end of compression stroke on concentration of soot and NOx on diesel engines, as a basis for building a set of diagnostic parameters to assess engine technical condition in use. For diesel engines, pressure of the end compression stroke at fuel injection timing directly inter-depends on spray structure leading to change of the formation combustion mixture process and burning fuel, thus affecting two types of engine emissions which are soot and NOx. Experimental research results on 4CHE-Yanmar diesel engines show that, pressure of the end compression stroke is reduced 14% lower than standard, thus soot emissions increases 36,43%, However NOx emissions decreases 22,58%.
Author: ,
Code: JST-UD2019-204 | Page: 31-36 of Vol. 18, No. 1, 2020 |
AbstractAbstract - Based on the technical data and setting parameters of the protective relays at Truc Son solar power plant, the paper has used Etap software to build a simulation model with differential function, over-current function and under-voltage function for a transformer T1 (7UT86, 7SJ86, REF615), a 475 feeder (REF615) and an Inverter (IKI30) to evaluate trip time coordination of main and backup relay protection near short circuit fault location by using results of single-phase earth fault, 2 phase earth fault, 2 phase and 3 phase fault that occur at 6 different positions. Based on the results, the paper recommends using the under-voltage function with an IDMT characteristic to improve the trip time of relay RL431, RL475, to reduce the error of causing the relays to lose selection in operation and improve the reliability of the power supply.
Author: Lê Cao Linh Chi; Thị Thu Trà Trần; Tôn Nữ Minh Nguyệt; Lê Nguyễn Đoan Duy; Văn Việt Mẫn Lê*
Code: JST-UD2019-149 | Page: 37-42 of Vol. 18, No. 1, 2020 |
AbstractBrewing spent grains(BSG)are a by-product with high nutritional value from beer production-line and has been used for animal feeding. In this study, BSG are dried, sieved and then mixed with wheat flour with the ratio of 20% and 80% to produce high fiber biscuit. When the pore size of the BSG sieve is reduced from 0,60mm to 0,21mm, the protein content of the obtained biscuit increases; the total fiber and phenolic content is reduced while the lipid and ash content is similar to those of the control sample without BSG use. Decrease in particle size of BSG also leads to an increase in biscuit thickness and diameter, a reduction in product hardness but does not change the sensory score on the product preference. With the recovery yield of 85,6%, the 0,40mm sieved BSG are an appropriate dietary fiber source for partial replacement of wheat flour in the high fiber biscuit production.
Author: , , , Bùi Thị Minh Tú, Đặng Văn Nghĩa, Tôn Nguyễn Thành Sang
Code: JST-UD2019-223 | Page: 43-48 of Vol. 18, No. 1, 2020 |
AbstractAn electronic control system is set up to convert a traditional engine into a hydroxy enriched biogas dual port injection engine. Hydroxy addition into biogas improves the engine work cycle. CO concentration decreases linearly with HHO content but NOx concentration increases by parabolic relation with HHO content. Biogas enriched by 30% hydroxy is the best compromise between engine performance and pollution emission. The dual injection of hydroxy and biogas creates an advantageous distribution of H2 and CH4resulting in an improvement of engine performance. Increase of hydroxy content leads to a decrease of optimal advance ignition angle and reduces the range of its variation with engine speed.
Author:
Code: JST-UD2019-232 | Page: 49-54 of Vol. 18, No. 1, 2020 |
AbstractThe main objective of the study is to provide feasible measures for improving the microclimate and appearance for high-rise buildings by arranging small gardens, contributing to responding to climate change and excessive building density. The author has proposed reasonable solutions with specific examples for the development of green space in high-rise buildings. The main research methods which are referenced and used including: archival research (research related to documents stored in different achives), scientific observation (on realworld practice), experience-based analysis, method based on scientific evidences. The results of the study are feasible and can be applicable to high-rise buildings in Vietnam.
Author: Phan Thị Việt Hà, Huỳnh Thị Phương Thu,
Code: JST-UD2019-179 | Page: 55-59 of Vol. 18, No. 1, 2020 |
AbstractThe process of DHA and EPA enrichment for fish oil by enzyme includes several steps, among which hydrolysis of fish oil with non-specific lipase is usually used as the first step. In this study, the results of fish oil composition analysis by GC before and after the hydrolysis show that lipase from Carica papapa latex (CPL) was non-specific lipase and can be exploited in the first step of DHA and EPA enrichment procedure. Using designed experiment of Box-Hunter model, the optimized conditions of fish oil hydrolysis with CPL are determined as follows: temperature of 29oC and pH of 7.6; water/oil ratio of 1.36:1 and enzyme level of 1.34%. This study will be used as the essential step in application of CPL in DHA and EPA enrichment of salmon oil to produce functional food.
Author: Đinh Văn Nhật, Nguyễn Đắc Mỹ, , Minh Duc Le*
Code: JST-UD2019-224 | Page: 60-63 of Vol. 18, No. 1, 2020 |
AbstractKAM50 tractor has a 4-cylinder diesel type L4AL-D and a power of 50HP ( 37.3 kW) assembled by Thaco co. ltd. The engine is located in front of the tractor; therefore, it produces big noise and directly affects the driver’s health. Muffler is an important part of the exhaust system on vehicles. It is used to reduce the noise from engine and to control particulate matter pollution in exhaust gases. Regarding the mission and vision of THACO co. ltd on the abilities of designing and manufacturing vehicle components, designing an exhaust system with good functions of muffler is necessary and urgent. This paper presents a typical design of muffler for KAM50 engine. Hence, THACO co. ltd can use their production technology to manufacture the muffler for KAM50 tractor as comercial product.
Author: Đỗ Thị Thúy Vân, Phạm Văn Vượng, Lê Thị Thanh Phương, Đào Hùng Cường,
Code: JST-UD2019-214 | Page: 64-67 of Vol. 18, No. 1, 2020 |
AbstractMale flowers of Carica papaya are widely used in folk to treat respiratory diseases. In this research, male papaya flowers are collected in some places of Danang city and Quangnam province. Pretreated ingridients are fractionally extracted with methanol solvent. Total methanol extract is fractionally separated by solvents with increasing polarization: n-hexane, chloroform, dichloromethane and ethyl acetate respectively. This article is about the chemical compounds of chloroform extraction. Three known compounds, rutin (1), acid gallic (2), daucosterol (3) are isolated and determinated in structure from the chloroform extract of male Carica papaya flowers. Their structure are determined by analysis of MS, NMR spectra, and compared with the published data.
Author: Vũ Thị Tường Minh,
Code: JST-UD2019-154E | Page: 68-74 of Vol. 18, No. 1, 2020 |
AbstractIn the math program at high school, finding the limits of functions is a difficult problem but rather common and is often seen in high school as well as university exams. There are many different methods to solve such problems. One of them is the tangential method which is effective and often used in many cases. In this paper, we give some ways to create new problems about limits of functions by using the tangent equations and give a few comments to help students with finding solutions. We also give some examples for practice. Based on the comments, students understand the nature of some problems of find limits of functions more easily by using tangential methods.